Was Petula Clark ever featured in an American comic book? Yes, but it wasn’t a very good one, and I’d be surprised if she even knew her picture had been used.
The comic was a short-lived title called Go-Go, and it was an attempt by bottom-rung comics publisher Charlton in 1966-1967 to do a humor comic. Charlton was where Steve Ditko, Spider-Man co-creator and artist, went after leaving Marvel Comics in 1966. Ditko had previously done work for Charlton, before joining the Mighty Marvel Bullpen.